The Changing Face Of Defense In The NFL: Defensive Line

The Changing Face of Defense in the NFL: Defensive Line

Christian Barmore

The dynasty world is built around long-term leagues. We all love the idea of playing for years and years with the same people in the same league and using our football nous and knowledge to build serial winners.

This means that individual leagues often remain extremely similar over long periods of time. Minor rule changes may happen every year or two, but major changes are relatively rare. Most leagues don’t change things like basic scoring philosophy or the number of starters very much.

However, at the same time, the NFL is changing rapidly. How it deploys personnel, the sort of plays used, the types of players it favors to execute those things… all of these are in a constant state of flux.

This mini-series of articles is intended to show what those changes look like on the defensive side of the NFL and ask how your leagues and strategy can change to take account and advantage of them.

Overall front use

Generally, the football world is thought of as simply using two fronts. The 3-4 and the 4-3. If you’re reading this article, then you know what those mean. Most of the defensive press coverage and discussion will label each NFL team as being one or the other of those. Of course, that’s simplistic and most NFL teams use both at different times. However, there are also several other fronts that are commonly used in the NFL and this chart shows how that usage has changed over the past decade.

For reference:

Skinny: a front with fewer than three linemen. Mostly used in prevent or obvious passing situations.
NASCAR: a front that features only edge players and no interior linemen.
3-4 under/over: various versions of an odd front that combines principles from 4-3 and 3-4 defenses.
Edge-in: a four-man front where an edge player lines up on the inside for extra pass rush.

You’ll likely notice that the distribution of these has been relatively stable over time.

If we look at the same data in a different way, that’s even clearer:

But this article is about trends and changing NFL systems. So, what gives? To find out, we need to dig a little deeper.

Hybrid front defenses have taken over

A few years ago, it was considered revolutionary that a handful of teams (mostly the Ravens, Texans and Patriots) would use different fronts at different times. Now almost every team does that.

This chart shows the distribution of defensive front for every team in 2021.

There are more teams that use versatile, different fronts than teams that stick to just one or two.

You’ll also have noticed that there are precisely zero teams that use a three-man front more often than not. What constitutes a 3-4 defense is no more than a part-time front. Seven teams in 2021 were in a 3-front on 30% or more of their regular-season snaps: the Falcons, Bears, Jaguars, Chargers, Rams, Dolphins and Steelers. Of those teams, only the Rams were over 40%, and they were the first defense to do that in years.

Defining a team by something it does around 35% of the time seems a bit weird. It’s akin to defining people who get eight hours a night as being mostly asleep.

Focus on three-man fronts

Even so-called 3-4 defenses are only using that look occasionally. But we saw above that the proportion of NFL snaps in a 3-front is relatively stable. This seems confusing.

This next chart breaks out the total number of defensive snaps per season that had a 3-front on the field.

Although the difference between 2012 and 2021 is relatively minor, there is still a clearer trend. Between 2012-2016 the NFL averaged 7,479 snaps (23%) in a 3-front. From 2017-2021 that number shrank to 6,378 (19%).

So, the number is shrinking. At least a bit. That has to be a result of either:

Fewer teams are using a 3-front.
Teams that are using a 3-front are doing it less often.

Let’s look at the 2012 distribution as a comparison.

Straight away we can see a difference. This year just seven teams were using a 3-front over 30% of the time. Ten years ago, it was 12 – nearly half the league.

Eleven teams were above that 40% threshold that only the Rams hit in 2021. Four teams (the Texans, Colts, Jets and Steelers) even used a 3-front more over half the time. It was a different world.

So, we know that fewer teams are now using this sort of front.

This next chart shows the average snaps in a 3-front for teams that used it (with a threshold set at 300 or more snaps).

In the first years of the last decade, it was routine for 3-4 defenses to deploy that front 400-500 times per season.

In recent years, just hitting 300 is unusual and the teams deploying this system are doing it about 100 snaps less per season. That’s equivalent to 9-10% of a season.

It’s clear that 3-4 defenses are using it less, as well as there being fewer of them in the first place.

Implications for fantasy leagues

The first change is obvious. Everyone should stop (if they didn’t already years ago) stop trying to define and categorize players as 3-4 ends or nose tackles or 4-3 tackles. These guys are increasingly homogenous because of how defenses deploy fronts. Linemen are no longer just one of those things – they are all of them at different times.

So, players who habitually line up inside the offensive tackles can safely be lumped together for fantasy purposes. This is one of the key parts of True Position – using the DT position as a shorthand for all interior linemen.

A reminder: DLF’s very own Adam Tzikas has built a great tool that will make that change for you on MyFantasyLeague.

It’s relatively common for dynasty IDP leagues to use defensive formations where teams can choose to use a 4-3 or a 3-4 or something else. Those are a fun idea, but it’s worth challenging it. NFL defenses are not about a starting XI in a single package. They’re about flexibility and substitutions which points more towards best ball scoring and less rigid positional settings.

Dynasty strategic exploitations

The fact of the matter is that most of this information is not widely known or understood. Most football fans and fantasy players have absolutely no interest in league personnel trends. They are quite content to think of defense as simply being a binary 3-4/4-3 split. You can profit from this by telling people what they want to hear.

You can hype the value of the lineman you’re trying to sell by pointing out that he plays in a 4-3 defense and not in a 3-4. Going more granular than that is mostly not needed, you can just make that case for about three quarters of the league. Similarly, you can spin a yarn about how the guy you’re trying to sneak in as a throw-in will be asked to two-gap in 2022 which will hurt his efficiency. These are minor, tiny things, but they can help you build a story for your league-mates.

This is especially possible around your rookie draft. Most of your league mates will have only a hazy idea of how rookies will fit onto the team that drafts them. They will have read on some draft site that this player “profiles as a 3-4 DE” or some such. They will make certain assumptions about players on the back of this and you should absolutely support them in this.

As an example – last year the Dolphins drafted Jaelan Phillips in the first round. Your standard “3-4 or 4-3” fan probably thought there was a good chance that Phillips would be a “3-4 DE” and therefore play inside and be less productive. You can get these sorts of conversations going. Maybe even suggest that edge defenders on odd-front teams might be linemen. Okay, you might look a bit silly when the truth comes out, but what are you more interested in? Looking clever or getting good players due to misinformation?

Hopefully this article has given you a clearer idea of how the league is utilizing different fronts and what it means for the future, and that information can help you build better leagues and better teams in them.

Thanks for reading and good luck.

Author
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Tom Kislingbury

Contributor at Dynasty League Football

Being from England Tom only discovered American Football in the late 90s. From there he's gone from casual defender to devoted obsessive and likes to delve into deep data primarily about defensive players. He spends his days trying to pretend the spreadsheets and graphs he makes about football are actually work for his day job. No-one is fooled.

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